System for distributing successive electrical impulses to a multiplicity of output channels



R M. G. TOULON 2,541,134 SYSTEM FOR mswx-usuw-mc- SUCCESSIVE ELECTRICALIMPULSES TO A MULTIPLICITY OF OUTPUT CHANNELS Filed April 3, 1947 2Sheets-Sheet l INVENTDR PIERRE MARIE GABRIEL TOULON BY 7/ z 1 E uATTORNEYS Feb, 13,, 19511 Fehl3, 1951 v P. M. G. TOULON 2,541,134

- sYs'mM FOR DISTRIBUTING SUCCESSIVE ELECTRICAL IMPULLES TO AMULTIPLICITY 0F OUTPUT CHANNELS Filed April 3, 1947 2 Sheets-Sheet 2 INVE N TU R PIERRE NAME GABRIEL TOULOM ATT U RNEY5 Patented Feb. 13, 1951SYSTEM FOR DISTRIBUTING SUCCESSIVE ELECTRICAL IMPULSES TO A MULTIPLIC-ITY OF OUTPUT CHANNELS Pierre Marie Gabriel Toulon, Neuilly-sur-Seine,

France, assignor to Products & Licensing Corporation, New York, N. Y., acorporation of Delaware Application April 3, 1947, Serial No. 739,154 InFrance February 20, 1943 Section 1, Public Law 690, August 8, 1946Patent expires February 20, 1963 8 Claims. (Ci. 332-13) The presentinvention relates to systems for distributing, among a plurality ofindependent output channels, successive electrical impulses suppliedthrough a common input channel, these systems being of the kinddescribed in my copending U. S. applications, Ser. No. 739,018, filedApril 2, 1947, for Improvements in Signal Distributing Systems and Ser.No. 739,019, filed April 2, 1947, for Electrical Transmission Systemsand based upon the use of combined capacitors supplied with polyphasecurrent or currents.

An object of my invention is to obtain high voltage electrical impulsesin each of the independent channels. For this purpose, according to myinvention, I make use of a gas discharge tube (for instance a tubecontaining helium or mercury vapor at low pressure), in particular ofthe cooled type with a big condensation chamber, and the conductivity ofthe tube is controlled so as to last, on each successive impulse, for atime which is a function of the amplitude of the impulse to betransmitted or stored up. I vary the time at which the arc is struck inaccordance with the intensity of the current to be transmitted. Thistube conductivity control may be performed by means of a tube differentfrom that which serves to ensure the storing up of the impulse, butaccording to a preferred embodiment I make use of the multiple anode gasdischarge tube which distributes the impulses to the different channelsfor simultaneously ensuring amplification. I employ for this purpose theknown phase control" method for gas discharge tubes (a method which isnow very much employed in mercury vapor rectifiers, thyratrons) Controlof the grid potential, which ensures the starting of the current flow atthe desired time in the gas discharge tube, may be ensured by means ofsuitable auxiliary vacuum tubes. For instance, I make use of a saw-toothanode voltage, or of a tube having several control grids, one of thegrids receiving the modulation, and the second a saw-tooth voltage. But,according to a preferred embodiment of my invention, I make use of amultiple anode tube including at least two successive control grids: thefirst of the grids receives the modulation, whereas the second receivesa sawtooth voltage. At the same time each of the multiple anodessuccessively receives, as described in the above stated patentapplications, a complex voltage which passes through a positive value(peak of the curve) for an extremely short time interval in the courseof every period. This positive value is supplied successively to each ofthe anodes, which thus receive the amplified impulses.

The saw-tooth voltage is preferably obtained from oscillatorssynchronized to the scanning frequency, by means of a complex voltagegenerator as described in the above mentioned prior U. S. applications.

According to a preferred modification of my invention, the second gridis mounted like the anode of a relaxation oscillation generator, whichpermits of avoiding the use of a synchronized auxiliary voltage.

Preferred embodiments of my invention will be hereinafter described withreference to the accompanying drawings, given merely by way ofindication and in which:

Fig. 1 is a diagrammatical view of a-tube arrangement according to myinvention;

' Fig. 2 is a curve showing the form of saw-tooth oscillation preferablyused according to my invention;

Fig. 3 is a diagrammatical view of an arrangement for compensating forparasitic capacities;

Fig. 4 shows a modification of the arrangement of Fig. 1 embodying theuse of a two grid tube.

For certain applications, and in particular in the case of a high speedsignal distributor intended to supply the vertical conductors of a television receiving screen, as described in particular in my French PatentNo. 860,481 of June 28, 1939, entitled Improvements in big screentelevision receivers, it is necessary to obtain in each of theindependent channels a relatively high voltage (at least about onehundred volts). As the capacity of said vertical conductors is ratherhigh (for instance 250 electrostatic units), in view of the high rate ofthe impulses (if the frame includes for instance 600 horizontal linesscanned twenty-five times per second the rate of the impulses is 15,000per second) it is necessary to obtain a relatively high power in each ofthe channels (for instance 0.5 watt). The multiple anode distributingtube which feeds several of these channels simultaneously (for instancein the case of an arrangement including 800 points per line and 10distributing tubes having each 80 anodes) must therefore be able tosupply a very substantial power (theoretically 40 watts, but actuallymuch more as a consequence of the bad transformation output).Furthermore, the supply tube must have a very low internal resistance,as the instantaneous current in the tube is to reach very high values(eighty times 1.5 milliamperes, i. e. milliamperes approximately).Accordingly, when high vacuum tubes are employed, it is necessary tomake use of very big ones. Fig. 1 clearly shows the advantage resultingfrom the 8 woof gas discharge tubes of the kind including a controlgrid. In these tubes, and according to a known method, it is possible toobtain a progressive modulation by controlling, for each alternation andas a function of the impulse amplitude, the time at which the arc isstruck. The supply voltage may be an alternating one but it may alsohave any complex shape provided that it passes through zero. Fig. 1shows the application of this principle to my invention. I have shown atI the cathode, at 82 the control grid, at 08, 08', 88" some of themultiple anodes. According to the method above referred to, each of theanodes is given a complex voltage (diagrammatically represented by 84,84', 64") having at a given time a very sharp positive maximum, thesetimes occurring successively for the respective anodes. These voltagesare obtained through the use of energizing distribution devices 65, 88,81, 88 and 85, 88, 81' and 88' as already described in my abovementioned U. S. applications. But, according to the present invention,the distribution device which supplies the successive impulses (comingfrom the common input channel) is no longer caused to act upon thecathode SI of the multiple anode rectifier tube but upon the grid of a'control tube 12. I arrange so that each of the anodes becomes positiveduring the hatched period 84, 84', 84", etc. On the other handthestriking of the arc is delayed (according to the now conventionalmethod of phase grid control) more or less (at 69, 89', 89") undercontrol of 'the modulation so that the mean value (hatched portion) ofthe current individually supplied to each of the anodes becomes afunction of the impulse amplitude.

In order to obtain this result, I make use, on Fig. l, of an amplifiertube 12 on the plate of I which a saw-tooth voltage is impressed by agenthe tube grid, while saw-tooth generator I acts upon the plate. Theplate current is shown by curve I5, 15" and the voltage drop acrossresistance I3 controls the grid potential of tube 82 in'such manner asto cause the arc to be struck at the desired time. The hatched portions89, 89', 69" thus have respective areas which correspond to theamplitudes of the successive impulses.

The current thus supplied through each anode has for its effect to storeup, owing to resistors I0, 1!,19", in each of the line condensers (80,80', 80") a charge which depends upon the impulse amplitude. Suitablemeans (not shown) .are then provided todischarge these condensers.

In order to produce saw=tooth voltage l0, I may, according to myinvention (Fig; 2) have recourse to a complex voltage generator basedupon the principleof the static voltage distribution described in myabove mentioned prior U. S. applications. I superimpose on thefundamental sinusoid 88 its first harmonic (or several harmonics ifnecessary) with a suitable choice of amplitude and phase, so as toobtain a resultant curve It which diifers but little from the desiredsawtooth shape (dot and dash lines).

cording to another feature of my invention,

the voltage induced by the tube capacity in the anodes which receive theimpulses is constantly balanced by a voltage of opposite sign equal (orproportional) at any time to the instantaneous value of the impulse.Fig. 3 shows a device for generating this compensating voltage. On thisfigure, 05 represents the coil through which are supplied the highfreqency waves which carry the modulation. I make use of two oscillatingcircuits coupled with this coil and tuned to the carrier frequency: 88and 89. The flrstof these circuits supplies a rectifier 90 which feedsimpulses of a given sign to a resistance 9|. These impulses are fed tothe cathode 92 of the multiple anode distributor tube. The secondoscillator circuit 86 has its output connected to a second rectifier 81which supplies oscillation of opposite sign to a resistor 88. Thevoltage thus obtained is to exert upon anodes 80, 94, etc., an influencecapable of compensating that exerted by cathode 92. For this purpose, Imake use of a capacitor 95, 95' of a capacity equal to that of theparasitic capacitor 921-94 (if voltage 88 is equal to that of 9|). If,on the contrary, the voltage of 88 is different from 9|, I make use ofinversely proportional capacities.

As in the preceding arrangements, I produce in anode 94, 94', etc., acomplex voltage by means of capacitors 98, 98', etc. The utilizationcircuit is connected through a rejector coil 99. A capaeitor 91 and areactance coil 91' compensate the induction produced in the utilizationcircuit by capacitor 98. The voltages necessary for obtaining theseinductions are obtained from oscillators 98 synchronized with the lineimpulses 88. Discharge is obtained, accordingto a feature of myinvention, by means of a valve I00 the anode of which, connected with acapacitor I 02, receives a variable voltage of substantially rectangularform. This voltage is obtained through a system for the distribution ofpolyphase voltages of different frequencies supplied by an oscillatorsynchronized with impulses 98 and of a bias battery I06. The stored upvoltage corresponding to the impulse acts upon the grid of an amplifiertube I01 placed in the independent output line.

According to a preferred embodiment of my invention, the striking of theare at the desired time can be controlled without having recourse to anauxiliary control tube (tube I! of Fig.1), by making use of a gasdischarge tube having several control grids. Fig. 4 illustrates thisembodiment. The second grid III is connected with a relaxationoscillation generator, including a capacity H2 and a high resistance H3.The voltage impressed on the successive anodes II, II5,-I I8 isrepresented, as a function of time, by curves H1, H8, II9. ModulationI00 is applied between cathode H0 and the first grid I09. On the drawingI have shown two diflferent amplitudes I20 and I2! of the modulation(correspondingto two successive impulses. for instance).

Discharge of condenser H2 into anode grid III causes the striking of theare at the proper time, because the working'otanode grid I II dependsupon the potential of grid I09. Explanation of the operation appearsclearly by referring to Fig.

4: It has been supposed that at I23 the tube ceases to be ionized (toact as a conductor) due to the fact that the anode voltage II'I becomeszero. In these conditions, the potential of the condenser assumes agiven value I20, always the same. From this time on, as the tube acts asan insulating element, the voltage across the terminalsofcondenscr IIIgraduallyal 5 illustrated by inclined line l2l. then given a voltagesuch as I24, the arc is struck between cathode H and anode grid ill atpoint I25, which makes it possible for anode to discharge (hatchedportion I26). The tube keeps acting as a conductor as long as the anodeis discharging, that is to say as far as point I28. From this time on,the tube acts as an insulating element. Condenser H2 is again charged asrepresented by inclined straight line I29. If, at this time, controlgrid 109 has anothervalue, such as I21, more negative than its precedingvalue, anode grid III is energized at a later time, at I30, thusstarting a current 131 (hatched portion) in anode I it less importantthan the current which has been started in anode H5 and so on. It isthus possible to replace by a single tube having several grids arelatively complicated arrangement which would necessitate several tubesand means for producing a saw-tooth voltage.

The features above set forth can be employed in combination for ensuringhigh speed static distribution of the impulses in a multi-ele mentarytelevision receiver screen or in a multiplex telephony system.

In a general manner, while I have, in the above description, disclosedwhat I deem to be practical and eflicient embodiments of my invention,it should be well understood that I do not wish to be limited thereto asthere might be changes made in the arrangement, disposition and form ofthe parts without departing from the principle of the present inventionas comprehended within the scope of the accompanying claims,

What I claim is:

1. In a system of the kind described, the combination of a single inputchannel carrying successive electrical impulses of different amplitudesand equal durations, a plurality of independent output channels, agaseous discharge device having a cathode, at least one controlelectrode and a plurality of anodes, means connecting each of saidanodes to a different one of said output channels, means for impressingon said anodes one at a time and in succession periodic voltagevariations having sharp maxima, said voltage variations extendingpositively with respect to said cathode and means comprising saidcontrol electrode forv varying the time of current flow from each ofsaid anodes to said cathode in response to said periodic voltagevariations in accordance with the amplitudes of said impulses.

2. A system for distributing successive impulses from a single inputchannel to a plurality of independent output channels which comprises,in combination, a gas discharge tube including a cathode, at least onecontrol grid and a. plurality of anodes connected with said independentoutput channels respectively, means for impressing on said anodes, atthe frequency of the incoming impulses, periodical voltage variationswith sharp maximums occurring successively in a predetermined order forthe respective anodes, to bring said anodes successively intocooperating voltage relation with said cathode, and means, including atleast said control grid and a generator of saw-tooth voltage variationsconnected with said grid, for varying the time at which the arc isstruck in said tube in the course of each voltage variation period inaccordance with the amplitude of the incoming impulse corresponding tothis period.

3. A system for distributing successive impulses 11 grid I09 18 from asingle input channel to a plurality of independent output channels whichcomprises, in combination, a gas discharge tube including a cathode. acontrol grid and a plurality of anodes connected with said independentoutput channels respectively, means for impressing on said anodes, atthe frequency of the incoming impulses, periodical voltage variationswith sharp maximums occurring successively in a predetermined order forthe respective anodes, to bring said anodes successively intocooperating voltage relation with said cathode, an auxiliary controltube including a plate, a grid and a filament, means for impressing onsaid plate a sawtooth voltage of the same period as the above mentionedvoltage variations, means for impressing on said last mentioned grid thevoltage impulses from said input channel, and means for coupling theplate circuit of said auxiliary control tube with the grid circuit ofsaid gas discharge tube, whereby the arc is struck in said lastmentioned tube at a time in each period which varies in accordance withthe amplitude of the impulse corresponding to this period.

4. In a system of the kind described, the combination of a single inputchannel carrying successive electrical impulses of different amplitudesand equal durations, a plurality of independent output channels, meansfor distributing successive ones of said impulses from said single inputchannel to successive ones of said output channels comprising a gaseousdischarge tube having a cathode, a plurality of anodes and at least twocontrol electrodes interposed in current flow controlling relationbetween said cathode and said anodes, means for impressing periodicpositive voltage pulses on said anodes in succession and in synchronismwith said electrical impulses, means for impressing on one of said gridsa recurrent periodic saw-tooth voltage synchronized with said impulses,and means for impressing said electrical impulses on the other of saidgrids.

5. A system according to claim 2 in which said" generator of saw toothvoltage variations ispf the kind adapted to combine a fundamentalsinusoidal oscillation with at least one harmonic thereof.

6. A system for distributing successive impulses from a single inputchannel to a plurality of independent output channels which com prises,in combination, a tube including a cathode and a plurality of anodesconnected with said independent output channels respectively, means forimpressing on said anodes, at the frequency of the incoming impulses,periodical voltage variations with sharp maximums occurring successivelyin a predetermined order for the respective anodes, to bring said anodessuccessively into cooperating voltage relation with said cathode, meansfor impressing the incoming voltage variations on said cathode, andmeans for imparting to each of said independent channels a voltageopposed in direction and proportional in magnitude to the instantaneousvalue of the corresponding impulse voltage, to compensate that inducedin said independent channel by the capacity of said tube.

7. A system for distributing successive impulses from a single inputchannel to a plurality of independent output channcls which comprises,in combination, a tube including a cathode and a plurality of anodesconnected with said independent output channels respectively, means forimpressing on said anodes, at the frequency of the incoming impulses,periodical voltage variations with sharp maximums occurring successivelyin a predetermined order for the respective anodes, to bring said anodessuccessively into cooperating voltage relation with said cathode, meansfor rectifying the incoming voltage impulse variations and impressingthe rectified voltage on .said cathode, a plurality of condensers eachconnected on one side to one of said independent channels, means forrectifying said incoming voltage impulse variations in opposition withsaid first mentioned rectifying means and impressing the rectifiedvoltage thus obtained to the other sides of said condensers, tocompensate the voltage induced in said independent channel by thecapacity of said tube.

8. In a system of the kind described, the combination of a single imputchannel for supplying successive electrical impulses of successivelydifi'erent amplitude and equal duration, a plurality of independentoutput channels for successive ones of said electrical impulses, agaseous discharge device having a cathode, at least one controlelectrode, and a plurality of anodes, means connecting each of saidplurality of anodes to a diilferent one of said output channels, meansfor impressing on each or said anodes, one at a time and in succession,a similar positive voltage pulse, and means comprising said at least onecontrol electrode for controlling the duration of current flow from eachof said anodes to said cathode in accordance with the amplitude of thatone of said electrical impulses which occurs while that anode issubjected to one of said positive voltage pulses.

PIERRE MARIE GABRIEL TOULON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,932,606 Schramm Oct. 31, 19332,064,469 Haeff Dec. 15,1936 2,233,126 Haefl Feb. 25, 1941 2,307,188Bedford 'Jan. 5,1943 2,403,210 Butement July 2, 1946 FOREIGN PATENTSNumber Country Date 550,856 Germany May 23, 1932 497,367 Great BritainDec. 19, 1938 523,363

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